The architecture of Pi Mensae

Few days before the formal acceptance of this paper, an independent study about the architecture of the π Men planetary system was published⁽¹⁾. The results of that work, based on public data and not including the ESPRESSO observations, confirm the high mutual inclination of the orbital planes of π Men b and c. Our results are in agreement with those of Xuan & Wyatt and are characterized by a better formal precision.⁽²⁾

Pi Mensae, or π Men, is a yellow dwarf star in the constellation of Mensa. We know that it has a little planetary system, constituted by two planets (or, if you prefer, we discover only two planets orbiting around Pi Mensae): Pi Mensae b, one of the most massive planets ever discovered, about 14.1 the mass of Jupiter, and Pi Mensae c, a super-Earth, about 4.5 the mass of our planet.
In 2020, an analysis with Gaia DR2 and Hipparcos astrometry showed that planets b and c are located on orbits mutually inclined by 49°-131°, which causes planet c to not transit most of the time, and acquire large misalignments with its host star's spin axis⁽¹⁾.
This result was discovered also by an italian team⁽²⁾, but published just few days after on arXiv, using ESPRESSO (Echelle Spectrograph for Rocky Exoplanet- and Stable Spectroscopic Observations), a sèectrograph designed and developed in Italy by researchers of Brera's Astronomical Observatory at the Merate's laboratories. The instrument, mounted on the Very Large Telescope, has in a certain sense been tested with the planetary system of Pi Mensae, therefore, even coming seconds for a few, the result can be considered a success for the young ESPRESSO.

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1. Xuan, J. W., & Wyatt, M. C. (2020). Evidence for a high mutual inclination between the cold Jupiter and transiting super Earth orbiting π Men. Monthly Notices of the Royal Astronomical Society, 497(2), 2096-2118. doi:10.1093/mnras/staa2033 (arXiv) ↩︎ ↩︎

2. Damasso, M., Sozzetti, A., Lovis, C., Barros, S. C. C., Sousa, S. G., Demangeon, O. D. S., ... & Rebolo, R. (2020). A precise architecture characterization of the $\pi$ Men planetary system. A&A, Forthcoming article doi:10.1051/0004-6361/202038416 (arXiv) ↩︎ ↩︎